1. Technical Field
The present invention relates to a linear motor that gives a linear thrust to an object to be driven, utilizing electromagnetic induction.
2. Description of Related Art
A rod-type linear motor includes a rod with permanent magnets, and coils surrounding the rod, and gives a thrust force to the rod in the axial direction thereof utilizing electromagnetic induction arising from the magnetic field of the permanent magnets and current running on the coils.
The rod-type linear motor can be easily built in a small size, yet exhibits high performance because of the advantages such as simple structure and small cogging force from fluctuation of the magnetic flux. The rod-type linear motor is employed, for example, in a chip mounter of semiconductor manufacturing equipment.
In the aspect of the armature of the rod-type linear motor, for example Japanese Unexamined Patent Application Publication No. 2007-97295 (Patent Literature 1) discloses a linear motor including air-core coils connected on a wire connection plate and encapsulated in a resin.
As another example, Japanese Unexamined Patent Application Publication No. 2007-6637 (Patent Literature 2) discloses a linear motor including air-core coils arranged on a printed circuit board so as to constitute the armature.
Further, Japanese Unexamined Patent Application Publication No. 2009-100617 (Patent Literature 3) discloses a shaft-type linear motor in which coils are connected to a printed circuit board fixed to a flange portion attached to one of two divided semicircular yokes.
In the linear motors according to the Patent Literatures 1 to 3, the lead of the coil of the armature is connected to the circuit board. The circuit board is disposed in the axial direction of the rod (shaft). Such a configuration increases the width of the armature, which is disadvantageous to reduction in size of the armature.
In addition, in the case where the coil of each phase is not continuously wound, the phases are defined via the circuit board. In this case the number of connection points to the circuit board is increased, which degrades the wiring work efficiency for arranging the lead of each phase and the ground wire.